Application Research of High Brightness LED in Green Lighting Project

Abstract: According to the principle of colorimetry and the characteristics of L ED, the principle of color matching of three primary colors of light emitted by red, green and blue L ED tubes when high-intensity L ED illumination is applied is discussed. The C IE chromaticity system is used to realize the color matching principle. The calculation of the color of the three primary colors determines the color matching ratio of the three primary colors; according to the principle of human visual inertia, the brightness of the L ED is controlled by a pulse width modulation (PWM) control method, thereby realizing the control and adjustment of the gray level of the L ED color. Achieve the desired brightness effect.

0 Overview

Light-emitting diodes (L ED) are a wide range of electronic components. However, due to its low luminous efficiency and brightness, and the variety of luminescent colors, L ED was mainly used in the display of instrument status, numbers and texts before the 1990s. In the early 1990s, L ED chip manufacturing technology and packaging technology achieved significant development. L ED's illuminance reached cd level, resulting in the so-called high-brightness L ED. The illuminating color also covered the entire visible spectrum, greatly expanding. The scope and field of application of L ED. Many countries and regions in the world have begun to replace incandescent lamps and metal halogen lamps with ultra-high brightness L ED. They are widely used as traffic lights, warning lights, sign lights, high-position brake lights, tail lights, turn signals and instruments on automobiles and cars. Lighting and display of the disc. Some foreign companies have also produced lighting fixtures such as L ED bulbs, L ED lamps and small flashlights. So far, the luminous efficiency of white light L ED has reached 15~ 20 lm?W, which is equivalent to or higher than that of incandescent lamps. It has become possible to replace incandescent lamps with L ED.

Compared with incandescent lamps, L ED solid-state lamps have an excellent service life (up to 100 000 h), low energy consumption, high luminous efficiency, environmentally friendly, low maintenance costs, stable operation, etc. Green lighting source. Since the luminous flux of a single L ED tube is relatively small, it is relatively expensive to obtain a L ED tube for illuminance equivalent to an incandescent or fluorescent lamp. At present, solid-state lighting has not been fully developed, and the main factor restricting the development of L ED lighting is the brightness and development cost of L ED. With the development of L ED manufacturing technology and the continuous reduction of cost, L ED lighting will become more and more popular. High-brightness L ED has a broad development prospect and market for solid-state lighting.

1 Color matching principle of high brightness L ED

1. 1 color matching principle

A method of adjusting two or more colors to be visually identical to a certain color is called color matching. Colors can be mixed with each other. This mixing can be a mixture of color light or a mixture of dyes, and the results obtained by the two mixing methods are different. The former is called color addition and mixing, and the latter is color subtraction and mixing. The light of several colors stimulates the human visual organ at the same time or sequentially, and a new color feeling different from the original color is produced, which is a method of adding and mixing colors. Experiments have shown that it is most convenient to produce other colors with the three primary colors of red, green and blue. These three colors are the optimal three primary colors.

In the matching experiment of color light, the spectral composition of the color composed of the three primary colors may be inconsistent with the spectral composition of the matched color light. For example, white light mixed by three colors of red, green, and blue is visually identical to white light of continuous spectrum, but their spectral compositions are different. This color match is called a "metachromatic" color pairing. The color mixed from the three primary colors expresses only the appearance of the matched color, but does not express its spectral composition.

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